• Christoph Lameter's avatar
    Use ZVC counters to establish exact size of dirtyable pages · 1b424464
    Christoph Lameter authored
    We can use the global ZVC counters to establish the exact size of the LRU
    and the free pages.  This allows a more accurate determination of the dirty
    ratio.
    
    This patch will fix the broken ratio calculations if large amounts of
    memory are allocated to huge pags or other consumers that do not put the
    pages on to the LRU.
    
    Notes:
    - I did not add NR_SLAB_RECLAIMABLE to the calculation of the
      dirtyable pages. Those may be reclaimable but they are at this
      point not dirtyable. If NR_SLAB_RECLAIMABLE would be considered
      then a huge number of reclaimable pages would stop writeback
      from occurring.
    
    - This patch used to be in mm as the last one in a series of patches.
      It was removed when Linus updated the treatment of highmem because
      there was a conflict. I updated the patch to follow Linus' approach.
      This patch is neede to fulfill the claims made in the beginning of the
      patchset that is now in Linus' tree.
    Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    1b424464
page-writeback.c 28.3 KB